I've recently started the restoration of
another RCA TRK-12 TV, everything was going along smoothly
with replacing all the capacitors and out of spec resistors
until I got to the HV power supply. On the previous TRK sets
that I have rebuilt, the two HV condensers which are oil
filled .03uF @ 7500VDC units, were in good physical
condition and when under load worked fine. These two had to
be a problem, they were leaking oil. I looked for a way to
just connect replacements under the chassis, but because the
condensers extend under the chassis they are used as
terminals for parts of the focus resistor string.

So I decided to try rebuilding them (sounded
like a good idea at the time). What follows is a step by
step procedure to get them apart, work with some real NASTY
stuff inside, and then put modern HV condensers inside.

This is
the original condenser, the connection on the right extends
below the chassis and is used as a terminal point for the
focus resistor string, the ground connection is soldered to
the top of the can and connects to the chassis. The gaskets
which were meant to keep the oil in are made of cork, but
now are like rock and leaking.

When I
loosened the insulator from the can the oil started to leak
out of the body as the internal gasket around the ceramic
insulator had failed.

The first step in rebuilding the condenser
is to open it up. The condenser is attached to the chassis
by way of a conventional condenser mount that secures the
can around the circumference. I made the cut through the can
at this point, so the repair will not be noticeable when
re-mounted. The cut is made with a common hacksaw, put some
tick marks along the cut so it is easier to re-align the
parts during re-assembly. Cut as quickly as you can, as the
oil will start to leak out if you don't. It's a good idea to
lay the can on a rag or some other material to catch any oil
that leaks out while making the cut.

After the
cut and if you are careful, this is what you will have. An
open can with some very NASTY stuff to get rid of. This
document isn't going to tell you where or how to get rid of
this stuff, just get it out and clean the can and parts of
all traces of the oil. I used something called Lac-Off to
clean the oil off everything then Naptha to clean off the
Lac-Off residue. I would recommend using gloves, and lots of
rags or paper towels during the cleaning procedure.

After
removing the majority of oil, and cutting the foil leads to
the top section you can easily remove the condenser body
from the can and dispose of it.

Next
remove the insulating paper from the can and the small cut
off section, it will be replaced during the re-construction
by a HV fiberglass sheet. The main can paper insulator is
easy to remove by sliding a small screw driver between the
can and the paper and twist it away, then grab the paper
with needle nose pliers, twist and pull out and discard. Use
a small screw driver or pick to remove the paper from the
small section being careful not to deform the wall of the
can. Press the threaded rod out of the ceramic insulator and
then press the ceramic insulator out of the small section of
can. You may have to soak this piece in solvent to get the
parts to release. Once everything is apart clean thoroughly
in solvents.

Components cleaned of all traces of oil and
ready for assembly.

The
insulator is re-assembled with a small amount of hot glue
between the ceramic and the can section. I cut a small piece
of HV insulating fiberglass as a washer between the stud and
the ceramic. The complete insulator assembly is held
together by compression of the end nut. Index marks to help
with reassembly of the can will be hidden under the clamp.

Ready for installation of modern
replacements. I will be using three .01uF @ 8,000VDC units
in each can to come up with the required .03uF.

To make up the required .03uF @7500V unit, I
connected three .01uF @ 8000V units in parallel. The left
side leads were formed into a small flat disc that would
make it easier to solder to the flat head of the terminal
screw. The other ends were connected to include a long
single lead to feed through the hole in the top of the can.

The new capacitor bundle attached to the
terminal connection. I added a seam of hot glue to keep the
capacitors tight.

The inside of the can is wrapped in HV
fiberglass sheet, the extra sticking out of the can will
slip into the insulator cap piece. The fiberglass is
hotglued to the inside of the can to give some support when
the two sections are mated and glued together.

Here the two sections are assembled using hot
glue. After the glue sets the excess is trimmed from the
joint with a razor blade.

Here is the completed unit ready for mounting
on the HV chassis. The new ground connection was made from a
#16 stranded wire with the insulation removed.

The completed unit mounted on the HV chassis,
one more to go.

The total time to rebuild one unit was about
90 minutes, most of that was removing the original internals
and cleaning.